DE69909301T2 - USE FOR A HIGH FREQUENCY IDENTIFICATION SYSTEM - Google Patents

Abstract

Antenna shelf tape is disclosed for use with items having radio frequency identification elements or tags associated with items of interest. <IMAGE>

Description

The invention relates to applications for high frequency identification (RFID) systems and in particular the use of such systems in libraries.

Capture electronic article surveillance ("EAS") systems the presence of small electronic devices based on or arranged in an article of interest or by a person of interest, and are often found in retail or Library environments used to prevent theft or unlawful theft of deterring articles. These devices, commonly known as In the past, labels or markers are only known to have been with information related to the presence of the item contain. This information could be intermittent or continuous electronic interrogation of the label can be obtained. About the Years are based on how this query was run is, d. H. magnetic, magnetomechanical, by radio frequency (HF or RF) or microwaves, at least four different types of EAS systems has been developed. Of these four types it is used in most applications the highest through magnetic systems Security level has been provided. Magnetic labels can be used in or placed slightly hidden on an object difficult to grasp (because them for a shield, for Bending and compressive stresses are less susceptible) and are light can be deactivated and reactivated, creating a high level of security is provided and some information regarding the condition of the labeled Article can be provided.

Many users of EAS systems want more Get information as just information about whether there is a labeled item. You want z. B. also know which labeled item is present. detailed information in terms of the properties of objects, e.g. B. about their date of manufacture, their inventory status and their owner generally automatic handling and control systems optical bar or Barcodes transmitted. Although optical bar or bar code systems are inexpensive and effective, they have certain limits. Barcodes must be visible which limits the places where they are located can, and barcodes can slightly random or be deliberately covered. The area in which a detector detects the Barcode capture is also comparatively narrow. The Barcode is required for a capture possibly also be positioned appropriately. Also the bar code, because barcodes are common must be exposed, to enable detection susceptible for damage that lead to detection errors can. After all, several need to objects can be processed at the same time. Because of these restrictions are barcodes for some applications unsuitable or inefficient, e.g. B. for marking of library media.

Most recently, electronic ones Identification techniques (also called RF identification techniques or RFID technologies known) designed to account for the limitations of optical barcodes to wear. RFID systems are suitable for identification and tracking of objects, however, they are unsuitable for securing objects because most RFID systems work in frequency ranges (~ 1 MHz or above), in which the label easily outwitted can be. The security deficiencies associated with RF labels result themselves because, for example, by covering the label a hand or aluminum foil, or by just putting the label in a book is arranged, can be "shielded". Also battery powered RF labels can be blocked or shielded even though their performance is greater and shielding would be more difficult, therefore items with an RFID label unintentionally or deliberately to capture missed. This will make the labels effective as safety devices significantly reduced. RFID markers are also related to "smart cards". In Commercial applications are both contact smart cards as well contactless smart cards have been used. Smart cards tend to be a specific person rather than a labeled item assigned. With the security and tracking of a smart card (or a person who wears it) related features are those discussed above regarding RFID markers Characteristics similar.

The associated with RFID markers Security features are professionals in the field of RF and microwave based EAS labels known. A major effort has been made the disadvantages of RF and microwave based EAS labels to eliminate. Your performance as security labels, however, has not been improved. In the U.S. patent No. 5517195 (Narlow et al.) Entitled "Dual Frequency EAS Tag with Deactivation Coil "becomes a dual frequency microwave EAS label described that an antenna circuit with a diode and a Has deactivation circuit. The deactivation circuit speaks to a low-energy alternating magnetic field by a Voltage in the diode of the antenna circuit is induced to the To block the diode and the antenna, thereby deactivating the label. Although in the Narlow patent. et al. described, on a Capacitor or capacitance based label for some applications is suitable, it may lose electrical charge over time, what lead to it could, that this Label is activated unintentionally.

RF-EAS labels of the type described in U.S. Patent No. 4745401 (Montean et al.) Described have a magnetic element. The magnetic element changes the tuning of the label if it has been suitably magnetized by an attachment, thereby blocking the RF response of the label. Although these labels are suitable for certain applications, they do not meet the requirements for increased security and identification.

RF identification techniques are have been developed by many companies or companies, e.g. B. from Motorola / Indala (see U.S. Patent Nos. 5378880 and 5565846), Texas Instruments (see U.S. Patent Nos. 5347280 and 5541604), Mikron / Philips Semiconductors, Single Chip Systems (see U.S. Pat. Nos. 4442507, 4796074, 5095362, 5296722 and 5407851), CSIR (see EP-A2-0494114, EP-A1-0585132, EP-A1-0598624 and EP-A2-0615285), IBM (see US Pat. No. 5528222, 5550547, 5521601 and 5682143) and Sensormatic Electronics (cf. U.S. Patent No. 5,625,341). By these labels are intended to provide remote identification without one Battery is required. You work at frequencies in the range from 125 kHz to 2.45 GHz. The lower frequency labels (125 kHz) are moderately safe against shielding, they have due of bandwidth restrictions however, only limited RF functionality. In particular, work on Systems based on such markers are generally only reliable if there is only one label in the query area at a time. You are also tends to be large format and expensive to manufacture. At higher frequencies (typically 13.56 MHz, 915 MHz and 2.45 GHz) has the additional bandwidth available enables the development of systems the multiple labels in the query area within a short period of time reliable can process. This is for many product applications highly desired. In addition, some label designs meet the expectations that they relatively inexpensive producible and therefore for make a customer more attractive. But also these higher-frequency devices are susceptible to the above to varying degrees discussed shielding. Therefore can they don't provide the high level of security that is in certain Applications, e.g. B. in libraries, is required.

According to the discussion above it can be seen that numerous Applications for RFID labels exist in different environments where the identity of the labeled Object is important. For example, in the PCT release WO-A-99/05660, published on February 4, 1999 by Checkpoint Systems, Inc. an inventory or inventory system using items with RFID tags described. In the preferred embodiment described therein will use RFID tags in library materials suggested that then automatically by querying the RFID tag checked can be to identify the material. However, there remain several important or desirable Library or inventory functions described in this publication not described or suggested.

EP-A2-0740262 relates to an electronic one System with a circuit for processing a signal and with several antennas. Moreover several switches are provided, each between the processing circuit and a corresponding one of the antennas are connected. Everyone who Switch has a first and a second power MOSFET, wherein the source electrode of the first MOSFET with the source electrode of the second MOSFET is connected. The system also has a circuit which is intended to select one of the plurality of switches, the should be switched on.

EP-A1-0526038 relates to a detector arrangement for a Item inventory control system in which multiple sensors to detect sensitized markers are used, which are attached to the inventory items are. By processing signals from each of the multiple sensors a detection or detection pattern is provided to determine whether none, one or more than within the sensitivity range there is a marker.

The present invention, which in the independent claims 1 and 16, relates to antenna systems incorporating an RFID device in move objects of interest that are in the vicinity of the antenna system. The RFID antenna system is used in conjunction with objects an RFID tag and optionally a magnetic securing element is assigned. The devices and applications are under special reference described on library materials, e.g. B. on books, magazines and magnetic and optical media. Other uses of the present Invention are also contemplated.

The present invention is discussed below Terms of the attached Figures in more detail described in which similar Reference numerals similar Designate structures; show it:

1A and 1B schematic representations of RF identification labels;

2 a schematic view of a second embodiment of an RF identification label;

3 a schematic plan view of a combination label;

4 a block diagram of an RFID interrogation system interacting with an RFID tag;

5 . 6 . 7 and 8th Representations of combination labels according to the invention; and

9 and 10 Representations of exec Forms of the present invention.

Detailed description of the invention

In the embodiments described herein RFID tags are used in the present invention, and preferably combined RFID / magnetic security labels. Labels of this type are filed in US-A-09/093120 on June 8, 1998, entitled "Identification Tag With Enhanced Security ", assigned to the assignee of the present invention was and in the US filing, their priority claims the present application, incorporated by reference was described. In connection with the embodiments of the present Invention used magnetic, RFID and combination labels are described in detail in Section I below, and the embodiments The present invention will then be discussed in the section below II in detail shown.

I. Labels and items for use with embodiments of the present invention

By one in the section below II described, with embodiments Label used in the invention can be made by a single device both item information and effective security to be provided. They preferably have an element that responds to a magnetic interrogation signal and an element that responds to an RF interrogation signal. In one embodiment is also a magnetically responsive element Antenna for the element responsive to RF signals is provided. The expression "address" means in connection with the present invention that by the element understandable Information will be provided if there is an appropriate query field is exposed. The individual elements are shown below described, whereupon a combination label is described. As is made clear, can the embodiments described in Section II below of the present invention either only one RFID element or one Combination of an RFID element and have a magnetic security element.

A. The magnetically appealing element

The magnetically responsive element is preferably made of a ferromagnetic material with low coercive force and high permeability, e.g. B. from a material used in the strips sold by Minnesota Mining and Manufacturing Company, St. Paul, Minnesota (3M) under the trade designation "TATTLE-TAPE ^™ ". These strips or marker arrangements are described in several patents granted to 3M, e.g. See, for example, U.S. Patents No. 5331313 (Koning) and 3747086 (Peterson). Exemplary ferromagnetic materials with low coercive force and high permeability are permalloy (a nickel-iron alloy) and amorphous high-performance metals, e.g. Metals available from Allied Signal Company, Morristown, NY under the trade names Metglas 2705M and Metglas 2714A.

The magnetically responsive element can dependent on of the article to which the element is assigned, either a single or be a double status element. For example, certain directory books are allowed in Libraries cannot be removed from the library, so that a single status (cannot be deactivated) Markers would always show whether such a book has passed a query area. For others Articles, e.g. B. general library materials or commodities a double status marker arrangement may be required so that when the Item was processed appropriately, the marker can be deactivated can to prevent collection by the query source. A Dual status functionality is available in general by adding sections of a magnetic material with higher coercive force nearby the magnetic material with the low coercive force, as described below and in the Peterson patent mentioned above becomes.

Certain magnetically appealing Elements have the ability to quickly switch the magnetic orientation when it is a low frequency alternating magnetic field (e.g. 50 Hz to 100 kHz) pass through, and generate a predetermined characteristic response by receiving coils detected by a detector can be. The switching function of the marker arrangement is by the Controlled magnetization state of the elements with high coercive force or "relay or magnet armature elements" ("keeper"). If these relay or magnet armature elements are magnetized, the ability of the marker, within the magnetic alternating field of the query area switching back and forth, changed, so that the Markers are typically not detected. If the relay or Magnetic armature elements are demagnetized, the marker can perform the switching function run again, So that the Query source can detect the presence of the marker. The relay or magnet armature elements are provided in various ways, such as in the art is known.

The marker assembly may also have an adhesive on one or both sides thereof to enable the marker to be adhered to a book or other article. The adhesive layer (s) may be covered by a removable liner to prevent the marker from adhering to a non-intended surface before being applied to the intended surface. These and other features of the marker assembly are described in U.S. Pat. 3790945 (Fearon), 5083112 (Piotrowski) and 5331313 (Koning), all of which were mentioned above.

Because it's difficult to get low-frequency Shield magnetic elements of this type in such a way that they avoid detection, are they for a wide variety of items can be used effectively when safety is important. Besides, they can more convenient, more complete and more often Deactivated and re-activated as markers using EAS techniques be so that they for use in certain applications (e.g. in libraries), where these properties are highly desirable are more appropriate.

B. That on radio frequency (RF) signals responsive element

RFID tags can either be active or passive his. An active label has an additional energy source, e.g. B. a battery in the label construction. This energy source allows it that the RFID labels also generate strong response signals in such areas and broadcast can, in which the RF query field is weak, so that an active RFID tag in a larger area ascertainable is. However, the relatively short battery life limits the service life of the label. The label is also through the battery bigger and expensive. A passive label wins that for supplying the label with power required power from the RF query field and uses this energy out by modulating the impedance of the in the query field arranged antenna to transmit response codes, which makes the Antenna of the reader reflected back Signal is modulated. Therefore, their coverage is more limited. Because passive labels for Many applications are preferred, the rest of this discussion is limited on this type of label. For However, it will be apparent to those skilled in the art that both types of labels are many have common characteristics and that both types of labels are related are usable with the present invention.

As in 1 has a typical passive element responsive to RF signals 10 typically two components: an integrated circuit 12 and an antenna 14 , The primary identification function is provided by the integrated circuit. It includes a program and circuitry for permanently storing the label identification and other desired information, interpreting and processing commands received from the query hardware, responding to requests for information by the interrogator, and assisting the hardware in resolving conflicts that arise when several labels answer the query at the same time. The memory of the integrated circuit can optionally be a read / write memory instead of a read-only memory, so that the information in the memory can not only be read out but also updated by the integrated circuit. Integrated circuits suitable for use in RFID markers are available from Texas Instruments (TIRIS or Tag-it product line), Philips (I-Code, Mifare and Hitag product line), Motorola / Indala and Single Chip Systems.

The antenna geometry and properties depend on the desired operating frequency of the RFID section of the label. For example, 2.45 GHz (or similar frequency) RFID tags would typically have a dipole antenna, e.g. B. the in 1A illustrated linear dipole antennas 14 , or the folded dipole antennas 14a , in the 1B on the element responsive to RF signals 10a are attached. 13.56 MHz (or similar frequency) RFID tags would become a spiral or coil antenna 14b use that as in 2 shown on the element responsive to RF signals 10b is attached. In any case, the antenna crosses 14 the RF energy radiated by an interrogation source. This signal energy transmits both power and commands to the label. The antenna enables the element responsive to RF signals to absorb sufficient energy to power the IC chip and thereby provide the response to be detected. The antenna properties and characteristics must therefore be adapted to the system in which the antenna is arranged. In the case of labels that work in the high MHz to GHz range, the most important property is the antenna length. Typically, the effective length of a dipole antenna is selected to be approximately half the wavelength or a multiple of half the wavelength of the interrogation signal. In the case of labels operating in the low or mid MHz range (e.g. 13.56 MHz) where a half wavelength antenna is impractical due to size restrictions, the important antenna properties are the inductance and the number of windings of the antenna coil. Good electrical conductivity is required for both types of antennas. Typically metals, e.g. B. copper or aluminum, used other conductors, e.g. B. magnetic metals, such as permalloy, are also suitable and actually preferred for the purposes of the invention. It is also important that the input impedance of the selected IC chip matches the impedance of the antenna to allow maximum energy transfer. More information about antennas is available to experts for example based on reference documents, such as. BJD Kraus, Antennas (2d ed. 1988, McGraw-Hill, Inc., New York).

wobei C = Kapazität (in Farad)
L = Induktivität (in Henry)
der gewünschten Arbeits- oder Betriebsfrequenz des RFID-Systems ungefähr entspricht. Der Kondensator kann auch eine verteilte Kapazität sein, wie in den für 3M erteilten US-Patenten Nr. 4598276 (Tait et al.) und 4578654 (Tait et al.) beschrieben ist. Eine verteilte Kapazität ist erwünscht, um die Etikettengröße, insbesondere die Dicke, zu reduzieren und die manuelle Montage zu minimieren.Often a capacitor 16 used to increase the performance of the marker as in 2 shown. The condenser 16 if available, tunes the frequency of operation of the label to a predetermined value. This is desirable in order to maintain a maximum work or operating area and to ensure compliance with operating regulations. The capacitor can be a discrete component or integrated in the antenna, as described below. In some label constructions, especially labels that are designed to work at very high frequencies, e.g. B. at 2.45 GHz, no tuning capacitor is required. The capacitor is selected so that when coupled to the inductance provided by the antenna, the resonant frequency of the combined structure is given by:

where C = capacity (in farads)
L = inductance (in Henry)
corresponds approximately to the desired working or operating frequency of the RFID system. The capacitor can also be a distributed capacitance as described in U.S. Patent Nos. 4,598,276 (Tait et al.) And 4,578,654 (Tait et al.) To 3M. Distributed capacity is desirable to reduce label size, particularly thickness, and to minimize manual assembly.

The label is responsive to RF signals during operation 110 , as in 4 represented by an EAS security system 100 queried, which is typically located near the location where the label is to be monitored. An interrogation area can be established by placing spaced detector plates across the exits of the room in which the labeled articles are located, near a conveyor belt that carries objects to be monitored, or at similar locations. Handheld detectors can also be used. A query source 102 (typically with a driver oscillator and an amplifier) is with an antenna 104 (sometimes referred to as a field coil) for transmitting an alternating radio frequency field or an interrogation signal in the interrogation area. The system 100 also has an antenna for receiving a signal (as an antenna 104 shown and sometimes referred to as a receiving coil) and a detector 106 for processing signals generated by labels in the query area.

The query source 102 transmits an interrogation signal 200 that is selected within known frequency ranges, which are preferred because they do not interfere with other applications and because they comply with applicable governmental or regulatory requirements. When the element responsive to RF signals receives an interrogation signal, it transmits its own response code signal 202 that over the antenna 104 received and to the detector 106 is transmitted. The detector decodes the response, identifies the label (typically based on a computer or other storage device 108 stored information) and performs processing or functions based on the detected code signal. Various modifications of the illustrated system are known to those skilled in the art, e.g. B. can instead of the single antenna shown 104 separate antennas for the query source 102 and the detector 106 be used.

With modern RFID labels Moreover essential storage capacities a conventional memory, sometimes in the Form of ROM memories or write-once memories, they enable however, the user prefers to overwrite the memory repeatedly update its content from a distance. The provided storage capacity can vary and be influenced the size and the Cost of the IC section of an RFID tag. Typically can be economical between 128 and 512 bits of total memory capacity can be provided. For example are licensed by one of Texas Instruments, Dallas, Texas under the Commercial name "Tagit" available RFID label in addition to 128 bits storage capacity, the for Information is reserved, such as the unique one Serial number of the label, version and manufacturer information and similar, 256 bits of storage capacity for one Programmable memory provided by a user. Similarly, by Philips Semiconductors, Eindhoven, The Netherlands available under the trade name "I-Code" RFID label 384 Bits of user memory are provided along with an additional 128 bits for the mentioned above Types of information are reserved.

Conventional memory can be used to increase the performance of an item identification system used, for example, in a library environment. Libraries currently identify objects by scanning an optical bar or bar code. The unique identification contained in this bar code is used to access a circulation database containing LAV (library automation vendors) software, where more detailed information about the item is permanently stored. Although this system has been highly developed and works very well in many applications, it can have two disadvantages. First, a connection to a circular database must be established to access information. This limits the availability of the information when an item is at a location remote from a connection to this database. Second, it can be used to retrieve information from the circulation database during periods of high data traffic sometimes an unacceptably long amount of time may be required. By storing certain critical information elements on the RFID label, both restrictions can be eliminated.

An example of information through which the performance of a library identification system could be improved if the information on the RFID label itself would be one Library identification number. Then, just by scanning of the RFID label without Access a database of a "home" library of an item quickly and be determined conveniently. Another example of information, the preferably on an RFID label itself, would be a code which determines whether the item is a book, a video tape, was a tape, CD, or other item. This code could for example one available from 3M, according to the 3M Standard Interchange Protocol specified media type code. Because the media type is known immediately, a library material management system could make sure a Item has been processed appropriately without delay and an inconvenience arises from going to a remote circulation database must be accessed. Other information examples that are suitable on an RFID label to be provided are known to those skilled in the art.

Another area in which RFID systems across from Identification is an advantage of systems based on barcodes of several objects. Using sophisticated software algorithms, RFID readers and markers work together to ensure that all objects in the query area of the reader without Intervention by an operator can be successfully identified. That ability enables the Development of numerous useful Applications in the field of inventory control, tracking and sorting objects, which are difficult due to identification systems based on barcodes, if any, would be implementable.

B. The combination label

As in the 3 and 5 to 8th is shown is in the combination label 20 combined a magnetically responsive element with an element responsive to RF signals to provide the advantages of both elements. Therefore, the two elements can be attached to an object of interest at the same time, reducing the cost. The combination label can include a pressure sensitive adhesive covered by a removable liner so that the combination label can be adhered to a surface of the article after the liner has been removed. In another embodiment, the label uses the magnetically responsive element as an antenna for the element responsive to RF signals. The magnetically responsive element, when used as an antenna, is electrically coupled to an element responsive to RF signals and may optionally be physically coupled to the element responsive to RF signals.

The combination label produced according to the invention can be queried in two ways. First, the RFID query source Use RF signals to request codes from the integrated circuit and receive. This information would be used for identification, for example the item the label is associated with and information about that show whether the item has been processed appropriately. Secondly could the label can be queried using a magnetic query field, to determine if the magnetic portion of the marker assembly was active. If the marker arrangement was active, the query source would be one Generate answer, e.g. B. a message that the marked item is not has been processed appropriately. Because the magnetic query regarding shielding is more secure than the RF query, would by the magnetic section of the combination label for increased security provided. This gives the characteristics of a magnetic and an RFID label provided in a single combination label.

In a preferred embodiment the combination label has a magnetically appealing element on that also acts as an antenna in the circuit of the responsive to RF signals Elements works. To provide both functions, the antenna material have a low magnetic coercive force, a very high one magnetic permeability (to serve as an efficient security element) and a medium one to high electrical conductivity (to function as an efficient antenna). In addition, the antenna geometry must be be compatible with both functions. In this embodiment could the antenna, for example, made of permalloy, an alloy made of nickel and iron.

In one embodiment, a 3M brand "Tattle-Tape ^™ " security strip or other equivalent magnetic element operating at 2.45 GHz or a similar radio frequency can be used as a linear dipole antenna. The length, width and thickness of this strip are selected so that they are adapted to the specific operating frequency and other parameters of the RFID chip used. Typically, the strip would be made from Permalloy (available from several sources, e.g., from Carpenter Specialty Alloys, Reading, PA under the trade designation "HyMu80") or an amorphous alloy, for example from Allied Signal Company, Morristown, NY under the trade designation 2705M is available, and its length would be between between 6.35 and 16.5 cm (2.5 and 6.5 inches). The integrated circuit connectors would be physically connected to the ends of the security strip. Electrical measurements of impedance and power gain have shown that such a magnetic stripe provides the same basic electrical properties as for copper or aluminum dipole antennas normally used with such a chip, so that both functions can be expected be carried out appropriately.

When the magnetically responsive element is used at least as part of the antenna of the element responsive to RF signals, the two elements are electrically coupled together. The electrical coupling can be established by a physical connection between several elements (as in 5 shown), or, if there is no physical connection, by contactless electromagnetic coupling (as in the 6 . 7 and 8th ) Shown. Contactless coupling can e.g. B. parasitic coupling, capacitive coupling or inductive coupling, wherein, for example, parasitic antenna elements, reflector and directional antennas, Yagi-Uda antennas or other suitable antenna configurations are used as antenna components.

This in 3 The combination label shown has coil windings made of a magnetic material. For example, the label could be a 13.56 MHz label e.g. B. with an antenna structure 14c be in the flux collectors are provided at the corners to improve the magnetic function of the label. Other types of flow collectors can also be provided.

This in 5 Combination label shown has a physical connection between the antenna made of a magnetically responsive material 22 and the integrated circuit 12 on. One or more relay or armature elements of the type described above can also be applied to the magnetically responsive material so that it can be selectively activated and deactivated to provide a dual status label. In the 6 shown antenna 22a is not physical with the integrated circuit though 12 or with the dipole antenna 23 connected, however, it is still electrically connected to the dipole antenna by parasitic dipole coupling to form a combination label 20a provide. The dipole antenna 23 may include a magnetically responsive material or a non-magnetically responsive material.

The 7 and 8th show embodiments in which more than one antenna 22 for an electrical coupling with antennas 23b respectively. 23c to be provided. In the in 7 shown combination label 20b shows the integrated circuit 12 a dipole antenna 23b on that with the antennas 22b is parasitically coupled. The antennas 22b are made of a magnetically responsive material, and the antenna (s) 23b can be made of a magnetically responsive material. In in 8th shown combination label 20c is an element of the in 2 shown type with antennas 22c parasitic electrically coupled. The antennas 22c are made of a magnetically responsive material, and the antenna (s) 23c can be made of a magnetically responsive material. Further modifications of these embodiments are easy to construct.

The total thickness of the combination label should be as small as possible be to allow the label inconspicuous can be placed on or in an article. For example the label can have an adhesive and between the pages of a book, with the label being desirable to train sufficiently thin, to prevent that Label is easily recognizable by looking at the end of the book. conventional ICs can about 0.5 mm (0.02 inches) thick, and the overall size of the label is preferred less than 0.635 mm (0.025 inch).

The combination labels according to the invention can be found in Roll form can be provided to allow individual labels to be packaged in one automatic application process applied sequentially to articles can be. This general system is for example in PCT publication WO-A-97/36270 (DeVale et al.). Individual combination labels, whereby one or more surfaces the labels can be covered with an adhesive (e.g. with a pressure sensitive Adhesive) separated from the roll and between two pages of a book in nearby its cover can be arranged. It can be a side spreader be provided to insert the combination label to facilitate and it can other options, e.g. B. sensors for detecting the position of various components in the system.

The combination label is probably particularly, although not exclusively, suitable for processing library materials. Lending or returning and returning library materials with an RFID tag of this type would be made easier and could possibly be done without human resources. In other words, the materials would be automatically issued or lent to a specific customer (who could himself have a library card with an RFID tag assigned to it) if the customer passes through a suitable detection area and are returned or transferred, when the customer re-enters the library with the appropriate materials. The label according to the invention can also support inventory management and analysis by enabling the library management to track materials immediately and continuously. This and other features of the inven tion are of course also suitable for other applications, e.g. B. for material handling in shops, department stores and for similar purposes.

According to another embodiment, through the combination label has both double status marker information by magnetic response (which indicates whether the magnetic Features of the label have been activated or deactivated) as also by responding to RF signals be provided (using appropriate software it is displayed whether the database or the memory of the RFID chip itself indicated that the Item has been processed appropriately).

The following are examples more information regarding in the embodiments described in Section II below labels used in the invention.

example 1

A combination label was made in accordance with the invention. A permalloy strip made by Carpenter Technology Corporation, Reading, Pennsylvania available under the trademark "HyMu80" Alloy was made on a test fastener attached by Single Chip Systems (SCS), San Diego, California will be produced. The strip was about 1.6 mm (0.625 inches) wide, 0.0254 mm (0.001 inches) thick and 10.16 cm (4 inches) long. The test fastener consisted of a 2.45 GHz SCS standard antenna connected to a light-emitting diode. The device was designed so that the light emitting diode light up would, when exposed to a 2.45 GHz field that is strong enough to power a typical SCS RFID tag, thereby an immediate visual indication of a suitable mode of operation of the power receiving section of the device is provided. After the SCS standard antenna through the prototype permalloy antenna was replaced, the light emitting diode shone at approximately the same field strength, whereby an appropriate functioning of the prototype has been confirmed.

Example 2

3 shows another embodiment of an antenna which is believed to be suitable for a 13.56 MHz construction. At this frequency, a coil antenna geometry is preferred. The spiral windings forming the coil are made either by (physical or chemical) etching, stamping or vapor deposition through a magnetic alloy mask, e.g. B. Permalloy. The straight "arm" or "leg" sections of the coil also serve as magnetically responsive elements in this construction. However, the reduced length of these metal elements in this geometry limits the effectiveness of the magnetic safety section of the device. In the in 3 In the illustrated embodiment, flux collector elements are added to the antenna coil at the corners to eliminate this limitation. In the 3 The construction shown would preferably have a capacitor, as described above, to tune the operating frequency of the antenna to the prescribed polling frequency.

The properties and parameters of the Antenna described in this example were made with the properties and parameters of known ones Antennas for Compared RF ICs, and because these properties and characteristics were similar, it is expected that the Antenna of this example will function properly in such an application would.

In those described below embodiments The present invention can either have a label with only one RFID element or a combination label can be used both have been described above.

II. Antenna system for an RFID interrogation system

A. General

The present invention relates to an antenna system for use with multiple objects from Interest, at least some of which have RFID elements. In a preferred embodiment the antenna system has: a continuous antenna band, that nearby of objects is arranged, the antenna band either permanently or releasably an RFID query source is connected, software for processing the information received by the antenna band and a controller, of the sections of the band activated to allow the RFID interrogation source to receive information from these sections of the band can get. These and other features of the invention are set out below in more detail described. Although within the scope of the present invention other applications possible the present invention is particularly suitable for inventorying of library items placed on shelves, and the present invention is essentially described in connection with this application.

B. System components

Some of the ones described in this section Components can may be optional in certain applications of the present invention.

1. With RFID tags provided items

The system is designed to collect information from and about items with RFID elements to receive data that can be contained in RFID tags (and alternatively referred to as RFID tags). In some embodiments, combination tags of the type described above can be used in place of or in addition to RFID tags. In the case of library materials, the RFID tags can be placed anywhere on the item, although it is preferred that the tag be placed a predetermined distance above the bottom of the item so that all such items are on a shelf are arranged, the RFID labels are arranged approximately in the same place. Preferred RFID labels do not have to be in direct visual contact with the RFID query source and can e.g. B. attached to a book on or near the cover. Because the antenna shelf tape is powered and the RFID elements in the labels are powered, smaller antennas can be used in the RFID labels, reducing both their size and cost.

2. RFID query source

The RFID query source is often called an "RFID reader" or RFID device referred to and is suitable for querying an RFID label in order to to receive information from it in a known manner. The RFID reader can be a stationary, portable or even a handheld device be and is suitable for using the antenna system according to the invention, to query the RFID labels. In other embodiments instructs the reader Moreover an antenna to enlarge the reading range of the reader. Lots Manufacturers make RFID readers forth who can read different types of markers. The RFID reader could be out a 13.56 MHz Commander RFID reader 320, manufactured by Texas Instruments, Dallas, Texas. A handheld reader module is available from I. D. Systems under the trade name "flx-msr", that although it has a low power consumption has a limited reading area, works as a portable reader. Another reading unit is different from that interacting with Phillips RFID markers Discovery kit available from Phillips, where Phillips the reading device However, it will probably not go on sale. Other readers that at higher Frequencies work, for. B. 2.45 GHz systems from single chip Systems and 900 MHz systems from Amtech. Each of these commercially available Query sources or other currently known or future developed ones Readers can with a suitably designed antenna shelf band as a query source be used. Because the RFID reader described here and the described antenna band must cooperate to objects of Successfully polling interest becomes the special one to be implemented Antenna band construction from the polling frequency (and possibly from other properties) of the RFID reader. So it’s very difficult specific statements about to make generally acceptable design parameters for antenna systems.

3. Software

After the RFID reader information from the RFID tags software is used to record the information on a selected by the user Way to process and store. This software is used to initially the reader and subsequently to query the labels. The software sends requests and commands from a host computer to the reader in order to determine operating parameters and health checks from the reader to obtain. The reader software also has security programs to verify that the to the reader and transmitted by the reader Commands valid Are commands or answers.

After the RFID device the RFID tag the device can read the item identification information transferred to a computer, which has LAV (library automation vendor) software. Examples of about 50 currently known LAV software systems are "Dynix", available from Ameritech Library Services, Provo, Utah, "Carl ILS "available from CARL Corporation, Denver, Colorado and "DRA", available from DRA, St. Louis, Missouri. LAV software enables libraries to Flow of Manage library materials through the library and assigns with customers, with library materials and their status and theirs Availability and with similar ones Information related databases.

4. Antenna

To query the RFID tags and enable the receipt of information from these labels, the present invention includes an antenna system that either can be continuous (and is therefore referred to as "RFID shelf tape", "antenna shelf tape" or simply as "shelf tape", although the shelf band is not necessarily adhesive like one normal strip material), or discontinuously, although a continuous antenna system for one ease of manufacture, application and operation is usually preferred is. Although the present invention uses discrete Antennas is feasible, it is referred to for simplicity described on a continuous antenna band.

In one embodiment, tags with RFID elements are placed in some or preferably all of the items within an area of interest and there is an antenna shelf band arranged at the position or near the objects. The antenna shelf band is preferably powered by an alternating current provided. If the RFID tags are queried by an RFID query source (which is either a single source for the whole area or consists of several sources), this source is then quickly able to obtain information about the presence or absence of the object and the identity of the Obtain item optionally for comparison with a database. As a result, an inventory is possible frequently or even continuously, which is particularly useful in libraries.

An antenna shelf band is in 9 shown and can be installed in a given area of interest on one, more than one or all shelves. The antenna shelf band can deliver additional power to the RFID elements, thereby reducing the overall power required to read the RFID elements in the labels assigned to the library materials. Readers that require less power can be made smaller and are therefore easier to handle. Instead of using a hand-held scanner that scans individual items sequentially, a group of items can be quickly read or scanned in one operation using the antenna tape, allowing a user to continuously track and inventory items. This enables an operator to determine in real time which objects are stored or stored or placed on shelves, which, among other things, would significantly simplify library inventory.

The antenna system according to the invention works preferably nearby different types of shelf materials. Made of wood or plastic Manufactured shelves can affect the antenna band, the construction of the antennas can however easily adapted in this way be that the exerted on the antennas different dielectric loads are taken into account, such as experts is known. For example an antenna tape with adhesive pad on the undersides of non-metallic Shelves are applied. In some libraries and data centers there will be metal shelves. Therefore, it is preferred that the antenna band is constructed so that it nearby of metal shelves works. In applications where the antenna band A suitable antenna design can be used on a metal shelf be required in the z. B. additionally a dielectric spacer layer is provided. The special one needed to optimize performance Construction is made by the for the antenna shelf band selected Depend on the operating frequency. For example compatibility with Metal shelves can be achieved by using the antenna band for RFID systems, operating at frequencies of approximately 13.56 MHz or less about 1.27 cm (0.5 inches) from the metal shelf. At frequencies above The shelf itself can effectively 13.56 MHz in the antenna construction be included and become an integral part of the antenna system. A alternative construction for Metal shelves would consist in that the antenna band on the shelf just above the books or other library materials.

For a suitable mode of operation must be in each individual antenna the arrangement have a suitable Q factor, as in the art is known. The Q factor describes the quality factor of the antenna and is a measure of the loss, the efficiency or the efficiency and the bandwidth of the antenna. A suitable Q factor would be depend on other components of the system: the Q factor of the markers, the Q factor of the query antenna assigned to the query source and the for the signal bandwidth required by the interrogation electronics.

In one embodiment, the antenna band according to the invention has a control circuit that allows the reader to query with a coordinate specific, activated section of the antenna band. That is, the reader asks RFID tags assigned to a specific section of the antenna band from and receives Information from these labels, and then ask another assigned (preferably adjacent) section of the antenna band RFID tags off, etc. This feature is called addressability and the control circuit may be a multiplex circuit exhibit. Addressable work is particularly important for monitoring areas useful, that are too big to be monitored effectively by a single antenna, though a single big Antenna system all items of interest at once. Using a would be such a single antenna system the query source is unable to determine the order of the items, she would be however, able to determine whether and which objects are being monitored Area are present.

As below with reference to 10 is explained in more detail, the controller would transmit an address to the antenna circuits. Only a specific antenna would then be activated to read the RFID tags using the reader signal. After an antenna was read, the multiplexing circuit would advance or increment to activate a next specified section of the antenna band. This antenna would support the RFID reader to query the RFID tags assigned to this section, etc. It may be desirable to overlap the areas of adjacent antenna elements so that, for example, objects 1 to 10 are closed in the first section ordered positions are read, in the second section the items 9 to 20 are read positions, in the third section the items 19 to 30 are read positions, etc. This arrangement is in 10 and is described in more detail below. The redundancy in the double interrogation of the same objects (in the above example, objects 9, 10, 19, 20) can be taken into account by the software and ensures that all objects are interrogated appropriately at the transition point between antenna elements. It would also be possible to query specific sections of the antenna band without using a multiplex circuit, for example by manually activating and deactivating these sections of the antenna band sequentially. This could be achieved with a simple switch.

Addressability is special useful for Determine the actual Order of queried objects, because they're specific items assigns a specific position. Because of the addressability Moreover a higher performance for each Antenna element provided. If no switches on the other Elements would exist would Circuit act as a power divider circuit. This would do that cause everyone Part of the entire line would be supplied, which reduces the probability that the labels read appropriately, is reduced.

The belt itself can be a continuous belt or can be in specific sections for use on specific Shelves. An example of a continuous belt would breakpoints on which the continuous antenna band material is separated could be provided that the Separation points do not affect an antenna element or interrupt an addressing circuit. At the point of separation could the circuit for connect to the reader through a simple mechanical or electrical connection with be added to the antenna band (by capacitive coupling). At the other end of the antenna band there would be a connector for fixing the number of elements arranged. If the circuit for the first Times would be used determined by an initialization step how many antenna elements exist and the circuit addresses would be set. If a given Band length used would, would the multiplex circuit and the connection with the reader electronics set and would be for one Ready to use.

According to another embodiment is through an RF amplifier an additional Signal power provided for querying the RFID label. The Antenna band leads RF energy to the labels and a reader then reads the Labels either by a hand device or by the antenna band even through the antennas in the band. Through the tape is additional RF energy is provided so that a handheld or a shelf reader the labels with greater efficiency can read. Another embodiment an amplifier is a basic RF amplifier that with the reader signal line is connected in series to deliver the power supplied to the antennas of the band increase and better signal processing or amplification of the retransmitted Provide signals and contribute to the retransmitted Interpret signal appropriately.

5. System integration

The antenna band would come with Interrogation and control electronics and therefore with suitable LAV software connect. As well as the size as well Cost of antennas used with RFID devices (query sources) could can be reduced, thereby eliminating power supply problems that through relatively large, unwieldy and expensive to manufacture copper wire antennas become. A continuous antenna band would eliminate the need for an inexpensive, easy-to-install antenna system meet the one set on shelves High resolution items from Z. Locate 12 cm (4 inches) or less for a 13.56 MHz system can. Using suitable hardware and software, the inventory could and position determination of objects in a predetermined Area fully automated become.

In one embodiment, an RFID inventory system works at a polling frequency of 13.56 MHz, this frequency within a frequency band that is for industrial, scientific or medical applications are reserved. By an appropriate change in the antenna construction, the present invention can be applied to a wide range of frequencies and applications can be used. The interrogation signal amplitude is preferably low enough to be magnetic Media, commercial (non-hardened) semiconductor devices (e.g. memory chips) and other electronic devices that outside this band work, not be adversely affected. The System fulfilled preferably all applicable FCC and EU directives for electromagnetic emissions.

As below with reference to 10 In more detail, the RFID reader, control circuitry, and other system components may be associated with either a specific segment or section of an antenna band or a handheld or other RFID device that can be attached to and detached from the antenna band. In embodiments in which a single antenna band is used for all areas of interest, the RFID device does not have to be separable from the band. In execution forms in which a multiple antenna band is used, a portable reader can be connected and activated to a first section of the antenna band and then separated from it and connected to a subsequent section of the antenna band. In a large, fully automatic application, in which a large number of antenna bands is used, a reading device can be assigned to a specific area in order to read all bands in this area, ie one reading device is provided per shelf. A central computer could then control all readers and the entire system. In another embodiment of the invention, an RFID device could be coupled to the antenna band system to poll the system without a physical connection. This contactless system would include a handheld RFID device that would be inductively coupled to one or more coupling stations that would be provided over the entire area of interest. The effect would be the same as an actual physical coupling, but additional advantages would be provided, e.g. B. less wear and tear or less wear on the system and a higher speed when coupled with multiple antennas.

10 shows an embodiment of an entire antenna band and interrogation system. Certain items of interest 1 through 20 are on a shelf 300 arranged, and each object has an associated RFID element. An antenna band 310 is on the shelf 300 attached and has individual addressable antenna elements 312 . 314 . 316 , etc. on. For applications in which the antenna band can be connected to and separated from the rest of the system, a port (e.g. a port 320 ) be provided. Sections of the system that are shown as separable from the antenna band, e.g. B. a reader 330 and a control circuit 340 , can be located either upstream or downstream of a port. The reader 330 asks the antenna elements 312 . 314 and 316 preferably sequentially when these sections through the control circuit 340 to be activated. The control circuit 340 preferably has a multiplex circuit. In the illustrated embodiment, as described above with reference to addressable antenna elements, a first antenna element can 312 query the items 1 to 10 assigned position, a second antenna element 314 query the items 9 to 20 assigned position, etc.

The through the reader 330 information obtained can be obtained by a suitable device, e.g. B. to a computer via a wireless or wired connection 350 transferred, the software and a database 360 having. The software may be LAV software or other software and preferably interacts with the database to obtain information about items 1 through 20 or to transmit information about these items to the database. The results can be shown to a user on a display 370 being represented.

The procedure for Specify and implement an antenna shelf band system according to the invention described. The first are prototypes of a flexible antenna band made that a desired one Has number of addressable individual antenna elements. This Elements or units are in a row along the ribbon arranged and can be a any desired Extend length. By more antenna elements will have a higher resolution (a greater ability specific objects assign specific positions) achieved by fewer antenna elements becomes a lower resolution receive. Two important functions to be handled are suitable ones Impedance matching from the first antenna to the last antenna to reach and maintain along the band and the same Performance for maintain all antenna elements to maintain a uniform reading area to obtain. These functions are easy to use by experts.

Second, a query electronics interface, an antenna interface construction and a method for addressing individual antenna elements developed on the band. Third is Computer software written to provide appropriate data collection from To enable antenna band. The fourth is the performance behavior of the prototype construction in the desired one Environment demonstrated and evaluated by z. B. a) the radiation pattern a single antenna element is imaged; b) the maximum Reading range of an individual antenna element is determined; c) interference between neighboring antenna elements is determined; d) the influence of the shelf structure, of books etc. nearby of the read antenna band evaluated on the detection behavior becomes; e) the efficiency of query power transmission along the band is determined; and f) the results of these examinations and measurements used to find the optimal antenna spacing and the optimal Determine antenna geometry.

RFID shelf tapes can also be used for applications in other areas. For example, the system could be adapted to locate specific RFID-tagged items in a collection of shelved video tapes, tapes, computer disks, or data cartridges, which may be required in a commercial or government data center, for example. Other possible applications are inventory management, asset tracking, logistics, and asset or cash sorting. It will be apparent to those skilled in the art that the specific embodiments described herein within the Scope of protection of the present invention can be modified.

Claims (22)

Antenna system for use with objects, each having an RFID element, the antenna system having a plurality of antennas, at least one of which is selected in order to query the RFID elements in the vicinity of the selected antenna (s) by an RFID device, thereby characterized in that the antenna system is provided in the form of a band extending in the longitudinal direction. The antenna system of claim 1, wherein the system has a power source provided by an RFID interrogation source supplied Performance is separated. The antenna system of claim 1, wherein the antenna system a multiplex circuit for selectively activating one or has several antennas for querying. The antenna system of claim 1, wherein the antennas overlapping along the length of the tape are arranged. The antenna system of claim 1, wherein the antenna system has at least one antenna consisting of coil antennas, spiral antennas, dipole antennas and microstrip patch antennas is selected. The antenna system of claim 1, wherein the band is the RFID system enables the order of the items to determine. The antenna system of claim 1, wherein the RFID elements queried essentially simultaneously by a central query source become. The antenna system of claim 1, wherein the band is through a hand unit is powered and activated. The antenna system of claim 1, wherein the antenna band attachable to a shelf by a mechanical fastening device is. The antenna system of claim 9, wherein the antenna band is magnetically attachable to a metal shelf. The antenna system of claim 9, wherein the antenna band an adhesive layer for has an attachment to a shelf. The antenna system of claim 1, wherein the system an RF amplifier to increase the power of the signal generated by the band. Inventory system with the antenna system according to one of claims 1 to 12 in combination with an RFID query source and software for processing of objects received information. The system of claim 13, wherein the items are library materials are. The system of claim 13 or 14, wherein the software has an algorithm to determine whether the queried objects are arranged in a predetermined order. Procedure for querying certain items that each have an RFID element, with the steps: (A) Providing a powered antenna system that in the shape of a lengthways extending band is provided and has several antennas, one or more of which can be selected to information about things nearby the selected antenna (s) provide; (b) Select a first antenna; (c) Querying the RFID elements that are in items nearby are assigned to the first antenna; and (d) Obtaining information about the objects nearby the first antenna from these RFID elements. The method of claim 16, wherein the method further comprising the step of: (e) using those obtained in step d) Information to update a database that contains information about the items. The method of claim 16, wherein the method after steps (a) to (c) further comprises the following steps: (E) Choose a second antenna; (f) querying the RFID elements that the objects nearby are assigned to the second antenna; and (g) Obtaining information about the objects nearby the second antenna from the RFID elements. The method of claim 18, wherein at least one Object is queried by the first and the second antenna. The method of claim 16, the method further comprising the step of: (e) determining whether the object is in position near the first Antenna is assigned. The method of claim 18, wherein the method run continuously to provide real-time information gathering on the items assigned to the positions of the first and second antennas are. The method of claim 18, wherein the method executed intermittently will provide information regarding the objects, assigned to the positions of the first and second antennas are in desired To provide intervals.